Author Topic: AS physics, Math Statstics1 Help me!! please  (Read 1226 times)

Offline bowser4

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AS physics, Math Statstics1 Help me!! please
« on: June 20, 2009, 06:13:26 pm »
First of all,
for AS physics

Q.a object is thrown 30degrees from the horizontal ground under the condition:no upthrust,no air resistance
gives a parabolic path.

By this,
Does the object have constant velocity?
If the answer is Yes,it has constant velocity,
isn't it wrong to say that the velocity of the object at the highest point is
ucos30degree?
because cos30 is 0.5 so the velocity becomes half of the initial velocity


For AS Mathematics Statistics1
If the question ask to draw a cumulative frequency graph,
when are we supposed draw a straight line or a smooth curve??
I know that for the question asking a polygon, its a straight line
and a curve, its a curve
but just asking for a graph, i don't know what to draw


And Lastly,
i know length is continuous
what about for
marks discrete or continuous?
hours discrete or continuous?
speed?

Please help me..  
« Last Edit: June 20, 2009, 06:15:16 pm by bowser4 »

Offline astarmathsandphysics

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Re: AS physics, Math Statstics1 Help me!! please
« Reply #1 on: June 20, 2009, 06:32:22 pm »
First of all,
for AS physics

Q.a object is thrown 30degrees from the horizontal ground under the condition:no upthrust,no air resistance
gives a parabolic path.

By this,
Does the object have constant velocity?
If the answer is Yes,it has constant velocity,
isn't it wrong to say that the velocity of the object at the highest point is
ucos30degree?
because cos30 is 0.5 so the velocity becomes half of the initial velocity


For AS Mathematics Statistics1
If the question ask to draw a cumulative frequency graph,
when are we supposed draw a straight line or a smooth curve??
I know that for the question asking a polygon, its a straight line
and a curve, its a curve
but just asking for a graph, i don't know what to draw


And Lastly,
i know length is continuous
what about for
marks discrete or continuous?
hours discrete or continuous?
speed?

Please help me..   

The object has constant horizontal velocity since the re are no horizonatal forces. In vector form v(t)=(ucos30)i+(usin30-gt)j
Ant the highest point v(t)=(ucos30)i an motion is horizontal.
For cumulative frequency curve or graph draw a smooth curve
length and hours and speed are continuous and marks are discrete

Offline astarmathsandphysics

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Re: AS physics, Math Statstics1 Help me!! please
« Reply #2 on: June 20, 2009, 06:33:07 pm »
Incidentally cos 30=0.866

Offline 123

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Re: AS physics, Math Statstics1 Help me!! please
« Reply #3 on: June 21, 2009, 01:17:06 pm »
Hey bowser4
Quote
For AS Mathematics Statistics1
If the question ask to draw a cumulative frequency graph,
when are we supposed draw a straight line or a smooth curve??
I know that for the question asking a polygon, its a straight line
and a curve, its a curve
but just asking for a graph, i don't know what to draw


And Lastly,
i know length is continuous
what about for
marks discrete or continuous?
hours discrete or continuous?
speed?

Please help me.. 
For CF graph its safer to draw polygon (ie. straight lines joining the plotted data)....its easier to do so too!! There is no strict rule  :P

Last 1:
It depends on what data is given in the question....if data has decimal points then its continuous ;if its just whole nos. then dicrete.

I have never heard of quarter or half marks....so i don't think marks is continuous.
Hours can be continuous but being discrete is more common.
Speed is mostly continuous....

Hey which exam board is this? normally questions on pointing out continuous and discrete don't come in exams!!
Examiners are not too fussy on these things too!! Just use common sense and u'll be fine  :D

Offline bowser4

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Re: AS physics, Math Statstics1 Help me!! please
« Reply #4 on: June 21, 2009, 01:43:58 pm »
Hmm. Thanks for the replies

But there are still some doubts left..

First of all, about 'astarmathsandphysics' reply
The object has constant horizontal velocity since the re are no horizonatal forces. In vector form v(t)=(ucos30)i+(usin30-gt)j
Ant the highest point v(t)=(ucos30)i an motion is horizontal.


What I am confused is
does the (t) written there stands for time??
If it stands for time, doesn't it mean the velocity increases with time??
Then doesn't it conflict with the comment that 'the object has constant horizontal velocity since there are no horizontal forces' ??

and at the highest point v(t)=(ucos30)i
But ucos30 = 0.866u
so doesn't it mean that the initial velocity decreased to the multiple of 0.866 at the highest point??
Can you explain to me a bit more?? Sorry..
« Last Edit: June 23, 2009, 02:52:34 am by bowser4 »